AU - nasiri, taher AU - riahinia, nosrat AU - neshat, narges AU - shaghaghi, mehdi AU - rasoli por, rasol TI - Carnapean Modal Semantics and its Implications for Ontology-Based Information Retrieval PT - JOURNAL ARTICLE TA - hii JN - hii VO - 8 VI - 3 IP - 3 4099 - http://hii.khu.ac.ir/article-1-3014-en.html 4100 - http://hii.khu.ac.ir/article-1-3014-en.pdf SO - hii 3 ABĀ  - Purpose: The purpose of this research is to identify and explain the Rudolf Carnap’s semantical and syntactical theories and its role on the theoretical and practical improvement of ontologies for the effective information retrieval. Methodology: Since the present study aims to survey Carnap’s semantics theory and shows the positive and effective points of semantic theory for the effective information retrieval based on ontologies, so the use of philosophical research method is inevitable. Philosophical research can have both "conceptual analysis" and "speculative" methods. The method that used in this research is conceptual analysis and its type is Qualitative methods. The research community includes all books and articles published by Rudolf Carnap in the field of semantics and the properties of ontological tools for the effective information retrieval. Findings: This study shows that Rudolf Carnap's deductive approaches to the problem of meaning can be used to develop ontologies for retrieval of textual information of resources and Rudolf Carnap's inductive approaches can be used to construct ontological systems in the field of experimental sciences. the rules of Rudolf Carnap's semantic system, such as the rules of classification of signs, the rules of formation of language, the rules of designation, the rules of value, the rules of determination, the rules of truth, The rules of selection and the rules of inference can be used in the structure of ontologies. Also, the rules of selection and the rules of relevance in Rudolf Carnap's semantic system are useful for the development of information retrieval in ontologies. the application of Carnap’s semiotic, syntax and semantics improve the accuracy and comprehensiveness of information retrieval in ontologies. Conclusion: The application of the Carnap semantic system in the structure of ontologies contributes to the theoretical and practical development of ontologies. CP - IRAN IN - LG - eng PB - hii PG - 1 PT - Research YR - 2021